# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the BSD-style license found in the
# LICENSE file in the root directory of this source tree.

# pyre-strict

import logging
from pathlib import Path
from typing import Optional

import executorch.backends.cadence.aot.ops_registrations  # noqa
import torch
from executorch.backends.cadence.aot.compiler_funcs import (
    prepare as prepare_fn,
    trace as trace_fn,
)
from executorch.backends.cadence.aot.memory_planning import (
    CadenceMemoryPlanning,
    print_memory_planning_info,
)
from executorch.backends.cadence.aot.quantizer.fusion_pass import QuantFusion
from executorch.backends.cadence.aot.quantizer.quantizer import (
    CadenceDefaultQuantizer,
    CadenceQuantizer,
)
from executorch.backends.cadence.aot.utils import (
    get_default_memory_config,
    MemoryConfig,
)
from executorch.devtools import generate_etrecord
from executorch.exir import (
    EdgeCompileConfig,
    EdgeProgramManager,
    ExecutorchBackendConfig,
    ExecutorchProgramManager,
)
from executorch.exir.passes import ToOutVarPass
from executorch.exir.passes.sym_shape_eval_pass import ConstraintBasedSymShapeEvalPass
from executorch.exir.program._program import _transform, to_edge

from torch.export.exported_program import ExportedProgram
from torchao.quantization.pt2e.quantize_pt2e import convert_pt2e

from .passes import apply_exir_ops_passes, apply_torch_ops_passes

from .utils import print_ops_info

default_quantizer = CadenceDefaultQuantizer()


def trace(
    model: torch.nn.Module,
    inputs: tuple[object, ...],
    dump_graphs: bool = False,
    ops_to_keep: Optional[list[torch._ops.OpOverload]] = None,
) -> ExportedProgram:
    """
    Trace the model with export and return an ExportedProgram.
    """
    if ops_to_keep is None:
        ops_to_keep = []
    program = trace_fn(
        model, inputs, is_qat=False, strict=True, ops_to_keep=ops_to_keep
    )

    if dump_graphs:
        logging.info("Graph before quantization:")
        logging.info(program.graph_module.graph.print_tabular())

    return program


def prepare_pt2(
    model: torch.nn.Module,
    inputs: tuple[object, ...],
    quantizer: CadenceQuantizer,
    dump_graphs: bool = False,
) -> torch.fx.GraphModule:
    """
    Trace and Prepare a model using the given quantizer.
    The quantizer must be supplied and be the same as the one used to
    fuse the model later, if applicable. If you do not expect that behavior,
    please use quantize_pt2 instead, which will instantiate a
    default quantizer for you if needed.
    Returns a GraphModule with the prepared model.
    """

    ops_to_keep = quantizer.get_ops_to_preserve_from_decomposition()
    traced_program = trace(
        model, inputs, dump_graphs=dump_graphs, ops_to_keep=ops_to_keep
    )
    prepared_program = prepare_traced_pt2(
        traced_program, quantizer, dump_graphs=dump_graphs
    )

    return prepared_program


def prepare_traced_pt2(
    program: ExportedProgram,
    quantizer: CadenceQuantizer,
    dump_graphs: bool = False,
) -> torch.fx.GraphModule:
    """
    Prepare a model using the given quantizer.
    The quantizer must be supplied and be the same as the one used to
    fuse the model later, if applicable. If you do not expect that behavior,
    please use quantize_pt2 instead, which will instantiate a
    default quantizer for you if needed.
    Returns a GraphModule with the prepared model.
    """

    prepared_model = prepare_fn(program, quantizer, is_qat=False)

    if dump_graphs:
        logging.info("Graph after preparation:")
        logging.info(prepared_model.graph.print_tabular())

    return prepared_model


def convert_pt2(
    graph_module: torch.fx.GraphModule,
    dump_graphs: bool = False,
) -> torch.fx.GraphModule:
    """
    Convert the model
    Returns a GraphModule with the converted model.
    """

    converted_model = convert_pt2e(graph_module)

    if dump_graphs:
        logging.info("Graph after convert:")
        logging.info(converted_model.graph.print_tabular())

    return converted_model


# Note: this is not meant as a primary API since it can create inconsistencies
# if the quantizer here is different from the quantizer used to prepare/convert.
# It is however useful for unit tests to separate the converted model from the
# fused model, to be able to get reference numerics.
# If this does not apply, please use quantize_pt2 instead.
def apply_pre_edge_transform_passes(
    converted_program: ExportedProgram,
    quantizer: CadenceQuantizer,
) -> ExportedProgram:
    """
    Fuse a converted exported program using the given quantizer.
    The quantizer must be the same as the one used to convert the model.
    If you do not expect that behavior, please use quantize_pt2 instead,
    which will instantiate a default quantizer for you if needed.
    Returns an ExportedProgram with the fused model.
    """
    # Get patterns and apply fusion of dq -> op -> q to qop
    # pyre-ignore[16]: no attribute
    patterns = [q.pattern for q in quantizer.quantizers]
    fused_program = _transform(converted_program, QuantFusion(patterns))

    return fused_program


# Note: quantizer is not optional here to force the user to supply a quantizer
# and ensure consistency is more likely to be maintained.
def get_fake_quant_model(
    model: torch.nn.Module,
    inputs: tuple[object, ...],
    quantizer: CadenceQuantizer,
    calibration_data: Optional[list[tuple[object, ...]]] = None,
    dump_graphs: bool = False,
) -> torch.fx.GraphModule:
    # Make the model inference mode by calling model.eval()
    model.eval()

    ops_to_keep = quantizer.get_ops_to_preserve_from_decomposition()
    program = trace(model, inputs, dump_graphs=dump_graphs, ops_to_keep=ops_to_keep)

    if dump_graphs:
        logging.info("Graph after trace:")
        logging.info(program.graph.print_tabular())

    # Get prepared graph module
    prepared_gm = prepare_traced_pt2(program, quantizer, dump_graphs=dump_graphs)

    # Calibrate
    # If no calibration data is provided, use the inputs
    if calibration_data is None:
        calibration_data = [inputs]

    for samples in calibration_data:
        prepared_gm(*samples)

    # Get converted graph module
    converted_gm = convert_pt2(prepared_gm, dump_graphs=dump_graphs)
    return converted_gm


def quantize_pt2(
    model: torch.nn.Module,
    inputs: tuple[object, ...],
    quantizer: Optional[CadenceQuantizer] = None,
    calibration_data: Optional[list[tuple[object, ...]]] = None,
    dump_graphs: bool = False,
) -> ExportedProgram:
    """
    Trace, prepare, convert and fuse the model using the given quantizer.
    If calibration data is provided, it will be used to calibrate the model. If
    not, the inputs will be used for calibration instead, which is useful for
    unit tests but should not be used for end-to-end use cases.
    Returns an ExportedProgram with the quantized model.
    Note: this function should not be called directly in general. Please use
    quantize_and_export_to_executorch for most needs.
    """
    # Instantiate the quantizer to CadenceQuantizer if not supplied
    if not quantizer:
        quantizer = CadenceDefaultQuantizer()

    # Get the converted (aka fake quant) graph module
    converted_gm = get_fake_quant_model(
        model,
        inputs,
        quantizer=quantizer,
        calibration_data=calibration_data,
        dump_graphs=dump_graphs,
    )

    # Apply quant fusion to the exported program
    program = torch.export.export(converted_gm, inputs, strict=True)
    fused_program = apply_pre_edge_transform_passes(program, quantizer)

    if dump_graphs:
        logging.info("Graph after quantization and fusion:")
        logging.info(fused_program.graph_module.graph.print_tabular())

    return fused_program


TO_EDGE_OP_EXCEPTION_LIST: list[torch._ops.OpOverload] = [
    torch.ops.aten._linalg_det.default,
    torch.ops.aten._linalg_svd.default,
    torch.ops.aten._native_batch_norm_legit_functional.default,
    torch.ops.aten.linear.default,
    torch.ops.aten.linalg_vector_norm.default,
    torch.ops.aten.unfold.default,
    torch.ops.aten.angle.default,
    torch.ops.aten.rms_norm.default,
]
TO_EDGE_PRESERVE_OPS: list[torch._ops.OpOverload] = [
    torch.ops.aten.rms_norm.default,
]


def _lower_ep_to_edge(
    expo_program: ExportedProgram,
    dump_graphs: bool = False,
    constant_methods: Optional[dict[str, object]] = None,
    core_aten_exceptions: Optional[list[torch._ops.OpOverload]] = None,
) -> EdgeProgramManager:
    """
    Lower an ExportedProgram to an EdgeProgramManager (in edge IR).
    """
    # Apply passes which transform the ExportedProgram before it gets lowered to edge.
    expo_program = apply_torch_ops_passes(expo_program)

    # Call to_edge to convert the graph to edge IR.
    # Note: dim_order is skipped (https://github.com/pytorch/executorch/issues/3704)
    edge_prog_manager = to_edge(
        expo_program,
        compile_config=EdgeCompileConfig(
            _skip_dim_order=True,
            # Allow specific non-core aten ops in the IR.
            _core_aten_ops_exception_list=TO_EDGE_OP_EXCEPTION_LIST
            + (core_aten_exceptions or []),
            preserve_ops=TO_EDGE_PRESERVE_OPS,
        ),
        constant_methods=constant_methods,
    )

    if dump_graphs:
        logging.info("Graph after Edge lowering:")
        logging.info(
            edge_prog_manager.exported_program().graph_module.graph.print_tabular()
        )
    return edge_prog_manager


# Export the model and lower it to an EdgeProgramManager (in edge IR).
def export_to_edge(
    model: torch.nn.Module,
    inputs: tuple[object, ...],
    dump_graphs: bool = False,
    constant_methods: Optional[dict[str, object]] = None,
    core_aten_exceptions: Optional[list[torch._ops.OpOverload]] = None,
) -> EdgeProgramManager:
    assert isinstance(model, torch.nn.Module), "model should be an nn.Module"

    # Export the model into an ExportedProgram.
    expo_program = trace(model, inputs)

    # Lower the model to edge IR.
    edge_prog_manager = _lower_ep_to_edge(
        expo_program, dump_graphs, constant_methods, core_aten_exceptions
    )

    return edge_prog_manager


def quantize_and_export_to_edge(
    model: torch.nn.Module,
    inputs: tuple[object, ...],
    quantizer: Optional[CadenceQuantizer] = None,
    dump_graphs: bool = False,
    constant_methods: Optional[dict[str, object]] = None,
    calibration_data: Optional[list[tuple[object, ...]]] = None,
    core_aten_exceptions: Optional[list[torch._ops.OpOverload]] = None,
) -> EdgeProgramManager:
    """
    Trace, quantize and lower a model/inputs pair to edge IR.
    """
    quantized_model = quantize_pt2(
        model,
        inputs,
        quantizer=quantizer,
        calibration_data=calibration_data,
        dump_graphs=dump_graphs,
    )

    return _lower_ep_to_edge(
        quantized_model,
        dump_graphs=dump_graphs,
        constant_methods=constant_methods,
        core_aten_exceptions=core_aten_exceptions,
    )


def _lower_ep_to_cadence(
    program: ExportedProgram,
    dump_graphs: bool = False,
    opt_level: int = 1,
) -> EdgeProgramManager:
    """
    Lower an existing ExportedProgram to edge IR and apply frontend optimization passes.
    """
    edge_prog_manager = _lower_ep_to_edge(program, dump_graphs=dump_graphs)
    cadence_prog_manager = apply_exir_ops_passes(opt_level, edge_prog_manager)
    return cadence_prog_manager


def export_to_cadence(
    model: torch.nn.Module,
    inputs: tuple[object, ...],
    dump_graphs: bool = False,
    opt_level: int = 1,
) -> EdgeProgramManager:
    edge_prog_manager = export_to_edge(model, inputs, dump_graphs=dump_graphs)
    cadence_prog_manager = apply_exir_ops_passes(opt_level, edge_prog_manager)
    return cadence_prog_manager


def quantize_and_export_to_cadence(
    model: torch.nn.Module,
    inputs: tuple[object, ...],
    dump_graphs: bool = False,
    opt_level: int = 1,
) -> EdgeProgramManager:
    """
    Trace, quantize, lower a model/inputs pair to edge IR and apply frontend
    optimization passes.
    """
    quantized_model = quantize_pt2(model, inputs)

    return _lower_ep_to_cadence(
        quantized_model,
        opt_level=opt_level,
        dump_graphs=dump_graphs,
    )


def export_to_executorch_gen_etrecord(
    model: torch.nn.Module,
    inputs: tuple[object, ...],
    output_dir: Optional[str] = None,
    opt_level: int = 1,
    mem_algo: int = 0,
    alloc_graph_input: bool = True,
    alloc_graph_output: bool = True,
    memory_config: Optional[MemoryConfig] = None,
    dump_graphs: bool = False,
) -> ExecutorchProgramManager:
    ep = torch.export.export(model, inputs, strict=True)
    return _lower_ep_to_cadence_gen_etrecord(
        ep,
        output_dir=output_dir,
        opt_level=opt_level,
        mem_algo=mem_algo,
        alloc_graph_input=alloc_graph_input,
        alloc_graph_output=alloc_graph_output,
        memory_config=memory_config,
        dump_graphs=dump_graphs,
    )


# Export the model and lower it to an EdgeProgramManager (in edge IR), and
# apply passes specific to Cadence DSP execution. Return both to print the
# differences.
def _lower_ep_to_cadence_gen_etrecord(
    ep: ExportedProgram,
    output_dir: Optional[str] = None,
    opt_level: int = 1,
    mem_algo: int = 0,
    alloc_graph_input: bool = True,
    alloc_graph_output: bool = True,
    memory_config: Optional[MemoryConfig] = None,
    dump_graphs: bool = False,
) -> ExecutorchProgramManager:
    edge_prog_manager = _lower_ep_to_edge(ep, dump_graphs)
    cadence_prog_manager = apply_exir_ops_passes(opt_level, edge_prog_manager)

    # Print some information to terminal
    print_ops_info(
        edge_prog_manager.exported_program().graph_module,
        cadence_prog_manager.exported_program().graph_module,
    )

    if memory_config is None:
        memory_config = get_default_memory_config()

    memory_planning_pass = CadenceMemoryPlanning(
        memory_config,
        opt_level=opt_level,
        mem_algo=mem_algo,
        alloc_graph_input=alloc_graph_input,
        alloc_graph_output=alloc_graph_output,
    )

    # Get executorch program after Cadence specific passes
    exec_prog: ExecutorchProgramManager = cadence_prog_manager.to_executorch(
        ExecutorchBackendConfig(
            memory_planning_pass=memory_planning_pass,
            emit_stacktrace=False,
            to_out_var_pass=ToOutVarPass(),
            extract_delegate_segments=False,
            sym_shape_eval_pass=ConstraintBasedSymShapeEvalPass(),
        ),
    )

    print_memory_planning_info(
        exec_prog,
        memory_config,
        opt_level,
        alloc_graph_input,
        alloc_graph_output,
    )

    if output_dir:
        _gen_etrecord(edge_prog_manager, exec_prog, Path(output_dir))
    else:
        logging.warning("No output directory provided, skipping ETRecord generation")

    return exec_prog


def _gen_etrecord(
    edge_program: EdgeProgramManager,
    et_program: ExecutorchProgramManager,
    output_dir: Path,
) -> None:
    etrec_path = output_dir / "etrecord.bin"
    try:
        generate_etrecord(
            et_record=etrec_path,
            edge_dialect_program=edge_program,
            executorch_program=et_program,
        )
        logging.info(f"Generated ETRecord at {etrec_path}")
    except Exception:
        # Any errors here shouldn't block the rest of the flow
        logging.exception("Encountered exception while generating ETRecord")
